MFC r304850, r305480, r324550-r324551, r324655, r324684: correct mis-merge

Some of these commits were improperly MFC'd in the sys/boot => stand
mega-MFC, others were simply missed. Correct that mistake now by manually
merging the few that were missed and record-only merge on the others.

r304850:
Unused variables and cstyle fix for loader dosfs

r305480:
Renumber the advertising clause.

r324550:
Add $FreeBSD$ to ancient sources that it's missing from.

r324551:
Move lib/libstand to sys/boot/libsa

Move the sources to sys/boot. Make adjustments related to the
move. Kill LIBSTAND_SRC since it's no longer needed.

r324655:
Remove the libstand directory which is now empty.

r324684:
Remove lib/libstand again, accidentally readded in r324683

MFC r334868: Add st_mtime, st_ino and st_dev for ufs_stat

MFC r329879, r329892

r329879:
libsa: Const-ify buffer argument of write(2) analog

r329892:
libsa: Change write(2)-alike prototype to match definition

Broken in r329879.

Apparently old GCC detects this, but modern GCC didn't. Mea culpa.

MFC r325834,r325997,326502: Move sys/boot to stand/

This is effectively a direct commit to stable/11, due to differences between
stable/11 and head. Changes to DTS in sys/boot/fdt/dts were often
accompanied by kernel changes. Many of these were also risc-v updates that
likely had many more dependencies to MFC.

Because of this, sys/boot/fdt/dts remains as-is while everything else in
sys/boot relocates to stand/.

r325834: Move sys/boot to stand. Fix all references to new location

r325997: Remove empty directories.

r326502: Document the sys/boot -> stand move in hier.7 and the top-level README.

MFC r324551: Move lib/libstand to sys/boot/libsa

MFC r309369,310850,310853:

libstand: dosfs cstyle cleanup for return keyword.
dosfs support in libstand is broken since r298230

PR: 214423
Submitted by: Mikhail Kupchik
Reported by: Mikhail Kupchik
Approved by: imp (mentor)

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

A new implementation of the loader block cache

The block cache implementation in loader has proven to be almost useless, and in worst case even slowing down the disk reads due to insufficient cache size and extra memory copy.
Also the current cache implementation does not cache reads from CDs, or work with zfs built on top of multiple disks.
Instead of an LRU, this code uses a simple hash (O(1) read from cache), and instead of a single global cache, a separate cache per block device.
The cache also implements limited read-ahead to increase performance.
To simplify read ahead management, the read ahead will not wrap over bcache end, so in worst case, single block physical read will be performed to fill the last block in bcache.

Booting from a virtual CD over IPMI:
0ms latency, before: 27 second, after: 7 seconds
60ms latency, before: over 12 minutes, after: under 5 minutes.

Submitted by: Toomas Soome <tsoome@me.com>
Reviewed by: delphij (previous version), emaste (previous version)
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D4713

Add a divisor parameter to twiddle() so that callers can request that output
only happen on every Nth call. Update the existing twiddle() calls done in
various IO loops to roughly reflect the relative IO sizes. That is, tftp
and nfs call twiddle() on every 1K block, ufs on every filesystem block,
so the network calls now use a much larger divisor than disk IO calls.

Also add a new twiddle_divisor() function that allows an application to set
a global divisor that is applied on top of the per-call divisors. Nothing
calls this yet, but loader(8) will be using it to further throttle the
cursor for slow serial consoles.

Eliminate __alpha__ leftover from libstand.

Remove California Regent's clause 3, per letter

Reset the seek pointer to 0 when a file is successfully opened,
since otherwise the initial seek offset will contain the directory
offset of the filesystem block that contained its directory entry.
This bug was mostly harmless because typically the directory is
less than one filesystem block in size so the offset would be zero.
It did however generally break loading a kernel from the (large)
kernel compile directory.

Also reset the seek pointer when a new inode is opened in read_inode(),
though this is not actually necessary now because all callers set
it afterwards.

Clean up error handling in libstand filesystem code to be more consistent:
- bzipfs and gzipfs now properly return errno values directly from their
read routines rather than returning -1.
- missing errno values on error returns for the seek routines on almost
all filesystems were added.
- fstat() now returns -1 if an error occurs rather than ignoring it.
- nfs's readdir() routine now reports valid errno values if an error or
EOF occurs rather than EPERM (It was just returning 0 for success and
1 for failure).
- nullfs used the wrong semantics for every function besides close() and
seek(). Getting it right for close() appears to be an accident at that.
- read() for buffered files no longer returns 0 (EOF) if an error occurs,
but returns -1 instead.

Update the second copy of libstand to deal with the new ufs2 superblock
format. The one in sys/boot/libstand is not connected to the build.

Approved by: re

This commit adds basic support for the UFS2 filesystem. The UFS2
filesystem expands the inode to 256 bytes to make space for 64-bit
block pointers. It also adds a file-creation time field, an ability
to use jumbo blocks per inode to allow extent like pointer density,
and space for extended attributes (up to twice the filesystem block
size worth of attributes, e.g., on a 16K filesystem, there is space
for 32K of attributes). UFS2 fully supports and runs existing UFS1
filesystems. New filesystems built using newfs can be built in either
UFS1 or UFS2 format using the -O option. In this commit UFS1 is
the default format, so if you want to build UFS2 format filesystems,
you must specify -O 2. This default will be changed to UFS2 when
UFS2 proves itself to be stable. In this commit the boot code for
reading UFS2 filesystems is not compiled (see /sys/boot/common/ufsread.c)
as there is insufficient space in the boot block. Once the size of the
boot block is increased, this code can be defined.

Things to note: the definition of SBSIZE has changed to SBLOCKSIZE.
The header file <ufs/ufs/dinode.h> must be included before
<ufs/ffs/fs.h> so as to get the definitions of ufs2_daddr_t and
ufs_lbn_t.

Still TODO:
Verify that the first level bootstraps work for all the architectures.
Convert the utility ffsinfo to understand UFS2 and test growfs.
Add support for the extended attribute storage. Update soft updates
to ensure integrity of extended attribute storage. Switch the
current extended attribute interfaces to use the extended attribute
storage. Add the extent like functionality (framework is there,
but is currently never used).

Sponsored by: DARPA & NAI Labs.
Reviewed by: Poul-Henning Kamp <phk@freebsd.org>

UFS indirect blocks are size u_int32_t, not daddr_t

#include <sys/disklabel.h> to get BBSIZE.

Remove 'register' keyword.

Add support for overwriting the existing contents of a file to the UFS
driver in libstand. This specifically does not expand or truncate files
since the filesystem may be dirty or inconsistent.

PR: kern/32389
Submitted by: Jonathan Mini <mini@haikugeek.com>
Sponsored by: ClickArray, Inc.

Add __FBSDID()s to libstand

Add a readdir function to the loader fsops vector, and implement the
functionality for some of the filesystesms.

* Enable old UFS compatibility code for booting from Digital Unix formatted
disks.
* Fix a whole raft of warnings, printf and otherwise.
* Make zalloc work for alpha (just a case of using the right typedef).
* Add some (disabled) malloc debug printing to stand.h.

Replace the old and extremely icky Mach/NetBSD allocator with a similarly
compact and much better one donated by Matt Dillon. Implement a simple
sbrk() which uses the existing setheap() api.

Remove the custom allocator from the UFS code. It wasn't working quite
right, and it shouldn't be needed with the new allocator.

Fix a serious problem with changing the value of already-existent
environment variables. Don't attempt to modify the supposedly-const
argument to putenv()

Fix an off-by-one sizing error in the zipfs code detected by the new
allocator.

Submitted by: zmalloc from Matt Dillon <dillon@backplane.com>

Allocate disk buffers using a custom allocator. The standard allocator fragments
extremely badly if disk buffers are freed back into the main heap and the alpha
bootstrap has a restricted address space which just ran out :-(.

Path arguments to *_open functions should be const, but we were mangling
them.

Submitted by: write-protected text segment in BTX

This commit was generated by cvs2svn to compensate for changes in r38451,
which included commits to RCS files with non-trunk default branches.

This is libstand; a support library for standalone executables (eg. bootstrap
modules).
Obtained from: NetBSD, with some architectural changes and many additions.